Device for acoustic detection of an arc

Abstract

The invention relates to a device for acoustic detection of an electric arc, comprising a tubular probe (10) adapted to be arranged beside an electrical apparatus on which an electric arc (AR) may be formed. An inner space (12) defined by a wall (4) of the probe extends along the length of the probe (10). The interior space (12) is filled with a fluid, and the interior space (12) is acoustically isolated from external noise by a wall (4). According to the invention, the probe (10) comprises at least one vulnerable region (15) on the periphery of the interior space (12) of the probe (10) and on the wall (4) of the probe (10), the at least one vulnerable region (15) being adapted to be degraded under the action of the arc (AR) so as to expose a passage (16) for sound waves (OA) generated by the arc to the interior space. The device further comprises at least one acoustic sensor (7) adapted to detect acoustic waves traveling through the channel (16) and propagating in the interior space (12) of the probe.

Description

Technical Field

[0001] The field of the invention relates to electrical equipment, in particular cables, in which arcs may occur.

[0002] The present invention more particularly relates to techniques for acoustic detection of electrical arcs. Background Art

[0003] In many industries, especially aviation, electrical wires are critical equipment in electrical systems. Various phenomena, such as brittleness of cables over time, manufacturing defects in the cables, assembly problems, or even voltage overloads on components external to the cables, can cause arcs to form on the cables. In turn, arcs can be the source of brittleness, lasting damage, or interference (electrical or electromagnetic interference) in electrical systems.

[0004] In order to be able to intervene as quickly as possible, manufacturers are looking for technologies for detecting the occurrence of an arc.

[0005] Arc detection technologies based on current measurement and voltage measurement are the most common. However, these technologies face the complexity of wiring (too many cables, uncertain wiring, etc.). This has led people to look for alternative or supplementary detection technologies.

[0006] Patent documents EP3232212, EP2896969 and EP3264116 describe devices for detecting arcs in electrical equipment, which are based on the detection of sound waves generated when an arc occurs. These devices are placed as close as possible to the location of a possible arc (in contact with an electrical terminal or in an electrical module of the device) to detect the occurrence of an arc at its location. Therefore, these devices are not suitable for detecting the occurrence of arcs over long distances, in particular arcs on cables of several meters or tens of meters in length. These devices make it even more impossible to locate the location where an arc is formed on a cable.

[0007] Therefore, a detection device is needed which at least partially overcomes the above-mentioned disadvantages. Summary of the invention

[0008] The present invention relates to a device for acoustic detection of electric arcs. The device comprises a tubular probe adapted to be arranged next to an electrical device on which an electric arc may be formed. An internal space defined by the walls of the probe extends along the length of the probe. The internal space or cavity is filled with a fluid and is acoustically isolated from external noise by the walls. The probe comprises at least one vulnerable area, the at least one vulnerable area being located at the periphery of the internal space of the probe and on the wall of the probe, the at least one vulnerable area being adapted to degrade under the action of the electric arc, thereby exposing a passage for the sound waves generated by the electric arc to the internal space.

[0009] The device also includes at least one acoustic sensor adapted to detect sound waves traveling through the passage and propagating in the interior space of the probe.

[0010] The tubular probe is hollow to allow sound waves to propagate through its inner space and then reach the acoustic sensor.

[0011] The probe can extend for a long distance, such as several meters. Since the sound waves propagate inside the probe, the sound waves (and thus the presence of the arc) can be detected at a great distance from where the arc is formed.

[0012] Thus, such a device allows the occurrence of an arc on an electrical device to be detected remotely. In particular, the device can be used to detect the occurrence of an arc along one or more cables, in which case the probe is arranged beside and along the cables. When the cables are assembled into a harness, the probe can be integrated into the harness.

[0013] The fluid filling the inner space of the probe may be air. Air has the obvious advantage of avoiding fluid losses and leaks. However, other fluids (gases, liquids or gels) may also be used, as long as the viscosity is not too high. In fact, the lower the viscosity of the fluid, the greater the distance the sound waves can propagate. In order to increase the detection speed, fluids may also be used whose sound waves propagate faster than air. This is the case in particular for helium and in general for any gas with a specific ideal gas constant higher than that of air.

[0014] When the fluid is a gas, the acoustic sensor may be a microphone.

[0015] The wall of the probe is generally tubular in shape. The wall surrounds the inner space of the probe and can be single-layer or multi-layer.

[0016] The probe has one or more vulnerable areas on the wall. Each vulnerable area is adapted to at least partially degrade under the action of the electric arc, thereby exposing a passage leading to the inner space of the probe. Then, the sound waves generated by the electric arc can penetrate into the inner space of the probe through the passage and propagate therein.

[0017] In certain embodiments, the at least one vulnerable zone is a fusible zone adapted to at least partially melt under the effect of the heat generated by the electric arc. However, in addition to melting, phenomena of material degradation, such as deformation or cracking, may also be considered without departing from the scope of the invention. It is sufficient that the degradation of the vulnerable zone caused by the electric arc results in the emergence of a passage for the acoustic waves to the inner space of the probe.

[0018] When the probe has a vulnerable region, the vulnerable region may extend along the probe. For example, the vulnerable region may extend parallel to the axis of the probe or extend spirally around the axis. When the probe has multiple vulnerable regions, the vulnerable regions may be regularly or irregularly distributed along the probe.

[0019] In certain embodiments, the at least one fusible region is formed by a fusible film that covers an opening through the wall. Such a film, when intact (i.e., unmelted), seals the opening and helps to isolate the interior space of the probe from external noise. By melting under the action of the heat generated by the arc, the film releases the opening, and the sound waves generated by the arc can then use the opening to reach the interior space of the probe and propagate therein.

[0020] In some embodiments, the fusible film has the ability to shrink under the action of heat, so that the film does not risk blocking the opening or the inner space of the probe when it melts. Therefore, the opening and the inner space of the probe remain unobstructed to allow the propagation of sound waves.

[0021] In some embodiments, the fusible film covers the entire wall from the outside or the inside. In other words, the film forms an inner or outer sheath around the wall of the probe. Among other advantages, this configuration simplifies the manufacture of the probe while enhancing the isolation of external noise outside the vulnerable area.

[0022] In some embodiments, the at least one vulnerable area is formed by an area of ​​reduced thickness of the wall. Due to the reduced thickness of this area, this area is more vulnerable than the rest of the wall and will degrade under the action of the arc.

[0023] When an arc is formed at an electrical device, the vulnerable area is degraded, and due to this degradation, a passage to the inner space is formed at the area. The acoustic waves generated by the arc pass through this passage and propagate in the inner space of the probe to the acoustic sensor located at a certain distance from the vulnerable area.

[0024] The acoustic sensor can be in contact with the interior space of the area, that is to say directly connected to the space, or indirectly connected to the space through a connection. For example, in some embodiments, a tube extends from the interior space of the probe through the wall to the acoustic sensor. The sound wave then passes through the interior space, then through the tube, and then reaches the acoustic sensor. This allows the acoustic sensor to be positioned at a certain distance from the probe. For example, this configuration has advantages when the probe is integrated into a cable harness. The acoustic sensor can then be positioned at the periphery of the harness or outside it. To facilitate positioning of the sensor, the tube can be flexible.

[0025] In some embodiments, the acoustic sensor is adapted to detect sound waves having a frequency less than 1000 Hz, in particular less than 500 Hz. Low frequency sound waves are preferred because when the wave propagates in the inner space of the probe, the attenuation of its amplitude decreases as its frequency decreases.

[0026] In some embodiments, the cross-section of the interior space of the probe is large enough so that the acoustic attenuation along the probe for waves with frequencies between 100 Hz and 500 Hz is less than 2 dB / m. This allows the acoustic sensor to be positioned at a considerable distance from the vulnerable area. For example, the distance between the acoustic sensor and the vulnerable area (i.e., if there are multiple vulnerable areas, the vulnerable area is the area farthest from the sensor) can be several meters, or even ten meters or more.

[0027] The distance may in particular be greater than two meters (2m), and more in particular may be greater than five meters (5m).

[0028] In some embodiments, the device further comprises a calculation unit configured to determine the propagation time of the acoustic wave from the degraded vulnerable area to the acoustic sensor based on the measurement signal of the acoustic sensor, and to infer the position of the arc based on the propagation time. When the device is used for a cable, this allows the location of the arc formed on the cable to be located.

[0029] The present invention also relates to an assembly, which comprises a detection device as described above and a wiring harness comprising a plurality of cables, wherein the probe is integrated into the wiring harness and arranged along the cables. In particular, the cables of the wiring harness can be distributed circumferentially around the probe.

[0030] In such an assembly, the detection device allows the formation of an arc to be detected at any one of the cables.

[0031] The foregoing features and advantages of the present invention and other features and advantages are set forth in the following detailed description which refers to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings are schematic and not necessarily drawn to scale, they are primarily intended to illustrate the principles of the invention. In the figures, from one figure to another, the same element (or part of an element) is identified by the same reference numeral.

[0033] [ Figure 1 ]This figure shows an example of a wiring harness in cross section.

[0034] [ Figure 2 ] The figure shows the process of arc formation in one of the cables in the wiring harness. Figure 1 The wiring harness in.

[0035] [ Figure 3]The figure shows an example of an acoustic arc detection device in axial cross-section.

[0036] [ Figure 4 ]This figure shows another example of an acoustic arc detection device in axial cross-section.

[0037] [ Figure 5 ]This figure shows the arc formation process Figure 4 Device in.

[0038] [ Figure 6 ]The figure shows Figure 5 The propagation of sound waves generated by an arc in a device.

[0039] [ Figure 7 ] This figure shows a top view along the direction of arrow VII Figure 3 or Figure 4 The probe of the device.

[0040] [ Figure 8 ]This figure shows the arc formation process Figure 7 The probe in .

[0041] [ Fig. 9 ]The graph shows the theoretical sound attenuation in air inside pipes with different inner diameters, depending on the frequency of the sound waves propagating in the pipe.

[0042] [ Fig.10 ]This figure shows another example of an acoustic detection device for electric arc. DETAILED DESCRIPTION

[0043] Specific embodiments of the proposed detection device are described in detail below with reference to the examples shown in the accompanying drawings. These embodiments illustrate the features and advantages of the present invention. However, it should be noted that the present invention is not limited to these embodiments.

[0044] In these embodiments, the detection device comprises a tubular probe 10 adapted to be arranged beside an electrical device, in particular a cable 1. The probe 10 is hollow, with the wall 4 of the probe surrounding and defining an inner space 12. The inner space 12 is filled with a fluid, in this case air.

[0045] In the example shown, in the absence of external mechanical stress, the probe 10 has the general shape of a rotating cylinder rotating with an axis X. The side surface or cylinder surface of the probe 10 corresponds to the outer surface of the wall 4. The inner space 12 of the probe or the cavity of the probe extends along the axis X. The inner space 12 has a diameter D1 corresponding to the inner diameter of the probe 10. The probe 10 can be flexible enough to be able to bend, in which case the axis X becomes a curve. The probe 10 includes a vulnerable zone 15 distributed along the probe, which is at the periphery of the inner space 12 of the probe 10 and is located on the wall 4. The vulnerable zone 15 can be regularly distributed according to the spacing E.

[0046] The device also comprises at least one acoustic sensor, in this case a microphone 7 with a vibrating membrane, which is connected to the interior space 12 via a tube 6 .

[0047] Figure 1 is a cross-sectional view of an example of a harness 20 including a plurality of cables 1. The cables are grouped in a harness group within an enclosure 2. A probe 10 is integrated in the center of the harness 20, and the cables 1 are distributed circumferentially around the probe 10. The cables 1 are in contact with the probe 10 or are at a short distance from the probe 10.

[0048] Figure 2 is with Figure 1 The same cross-sectional view, which shows the formation of an arc AR at one of the cables 1. The arc AR is schematically represented by a cone. The arc AR emits an intense but localized heat field. For example, for an arc greater than 50 amperes (A), the temperature can reach more than 700°C, and the thermal gradient can reach 500°C / mm from the start of the arc. The probe 10 is located near the cable 1 where the arc AR is formed, and the temperature on the surface of the probe 10 can reach several hundred degrees (°C).

[0049] The vulnerable zone 15 of the probe 10 is adapted to degrade under the action of the heat generated by the arc AR, so that a passage 16 appears towards the inner space 12 of the probe. The acoustic waves AO generated by the arc will then pass through this passage 16 (see Figure 5 and Figure 6 for example).

[0050] The vulnerable area 15 of the probe 10 can be produced in different ways. According to an exemplary embodiment (not shown), the wall 4 of the probe 10 is made of different materials, which are more or less heat-resistant, wherein at least one material that is most sensitive to heat is likely to be degraded or destroyed by the thermal field generated by the arc AR. The vulnerable area 15 is made of this sensitive material, while the rest of the wall 4 is made of at least one more heat-resistant material.

[0051] according to Figure 3In another exemplary embodiment shown, the composition of the probe 10 is uniform, and the vulnerable region 15 is an area of ​​reduced thickness of the wall 4. The reduced thickness is manifested by the presence of a hollow or cavity 25 at the vulnerable region 15. The cavity 25 can be present on the inner surface of the wall 4, such as Figure 3 The cavity 25 may also be formed on the outer surface of the wall 4, in particular for practical manufacturing reasons.

[0052] according to Figures 4 to 6 In another exemplary embodiment shown, the wall 4 is repeatedly perforated with holes 5 of diameter D2 and is surrounded by a non-perforated film 3. In other words, the film 3 encloses the wall 4 from the outside. The film 3 is fusible, that is to say, it is suitable for melting under the action of the heat generated by the electric arc. The melting temperature of the material constituting the film 3 is lower than the temperature emitted by the electric arc AR, while the melting temperature of the material constituting the wall 4 is higher than the temperature emitted by the electric arc AR.

[0053] Figure 5 The arc AR and the radiation of the acoustic waves OA generated by the arc AR are shown to occur near the probe 10. The heat generated by the arc AR causes the portion of the film 3 closest to the arc to melt, thereby exposing one of the holes 5. The uncovered hole 5 then forms a passage 16 for the acoustic waves OA to the inner space 12.

[0054] The melting of the membrane 3 must not lead to the pores 5 being filled, since in this case no channels 16 are formed. To avoid this, for example, the membrane 3 is chosen to be thin enough that the molten material cannot fill the pores 5. Alternatively or additionally, the material constituting the membrane 3 may be chosen such that the membrane 3 shrinks upon itself when it melts.

[0055] The wall 4 of the probe may be more or less flexible, depending on the intended use. For example, the wall 4 may be flexible enough to accommodate a given harness configuration 20.

[0056] For example, the wall 4 may be made of a polymer (e.g. an elastomer, silicone, fluoropolymer) or a metal. The membrane 3 itself may be made of acrylonitrile butadiene styrene (ABS), polyoxymethylene (POM) or polyethylene (PE). For example, a stretchable polyethylene membrane 3 with a thickness between 15 microns and 30 microns (whose melting temperature is comprised between 85° C. and 140° C.) may be associated with a flexible silicone wall 4 with a thickness of at least 1 mm (whose melting point is in the range of 300° C.). According to another example, the wall 4 may be made of polytetrafluoroethylene (PTFE) (whose melting point is in the range of 330° C.).

[0057] After the film 3 has been melted and the arc AR has been detected, a strip or a piece of the film 3 may be deposited on the exposed hole 5 to cover the exposed hole 5 so that the probe 10 can be reused.

[0058] Figure 6 The transmission of the acoustic wave OA through the channel 16 formed by the exposed holes 5, the propagation in the inner space 12 on either side of the holes 5 and the propagation in the tube 6 connected to the microphone 7 are shown. In the example in the figure, the holes 5 are circular and the holes 5 are arranged regularly and alternately on either side of the probe 10 at a spacing E along the axis X of the probe 10, so as to form two rows of diametrically opposite holes (the spacing between two adjacent holes in the same row is therefore twice the spacing E). Of course, other shapes and other distributions of holes can be considered, such as other (angular) positions and other (irregular) spacings of holes, without departing from the scope of the invention. The distribution of the holes 5 has an impact on the positioning accuracy of the arc AR. The spacing E between the holes 5 must allow one or more holes to be exposed when the fusible film 3 melts. For example, the spacing E can be millimeters or centimeters, depending on the temperature range of the exposed film. In particular, the spacing E between the holes 5 can be included between 2mm and 2cm.

[0059] The inner diameter D1 of the probe 10 is selected to limit the attenuation of the acoustic wave OA as it propagates within the probe 10 . Fig. 9 Theoretical sound attenuation in air in pipes with different inner diameters (similar to tubular probe 10) at ambient temperature and pressure is shown, depending on the frequency of the sound waves propagating in the pipe. Attenuation is represented as "Att" and is expressed in decibels per meter (dB / m). Frequency is represented as "F" and is expressed in Hertz (Hz). The inner diameter of the pipe is represented as "D1" and is expressed in millimeters (mm). Attenuation is provided by viscous heat loss in the acoustic boundary layer around the inner surface of the pipe. The thermoviscous phenomenon in the hollow pipe generates acoustic resistance and, likewise, attenuates the amplitude of the propagating wave. As shown in the figure, the larger the inner diameter D1, the smaller the sound attenuation. For example, a diameter D1 greater than 3.2 mm produces a sound attenuation of slightly less than 2 dB / m at 100 Hz. In this case, for a sound wave with a frequency of 100 Hz and a propagation distance between 1 m and 10 m, the amplitude attenuation varies between 2 dB and 20 dB.

[0060] In practice, the choice of the diameter D1 of the probe 10 depends on a compromise between the volume available for the probe (e.g., the volume available within the harness in which the probe is integrated) and the acceptable attenuation for the maximum propagation distance considered for the acoustic wave OA. For example, the diameter / propagation distance pair may be chosen to ensure that the acoustic attenuation is less than 20 dB. The maximum propagation distance considered is, for example, Figure 6 In the device of FIG. 1 , the distance between the microphone 7 and the vulnerable area 15A farthest from the microphone 7 is Fig. 9As shown, for a given diameter D1, the attenuation is more pronounced as the frequency of the wave increases. Therefore, it may be more interesting to favor the detection of low-frequency sound waves, since these waves are less attenuated when propagating in the inner space 12 of the probe 10. For this purpose, the microphone 7 used may preferably be selected to detect sound waves with a frequency below 1000 Hz, in particular below 500 Hz.

[0061] The diameter D2 of the hole 5 is also selected to limit the attenuation of the acoustic wave OA. In addition, the choice of the diameter D2 may be limited by the diameter D1 and the selected perforation technology. In practice, the diameter D2 of the hole 5 can be in the millimeter range. At this point, the inventor simulated a wave with a frequency of 200 Hz passing through a hole (similar to the hole 5) with a diameter of 1 mm (similar to the diameter D2), which is formed in the wall of a pipe (similar to the tubular probe 10) with an inner diameter of 4 mm (similar to the diameter D1). The simulation takes into account the assumption of monopole excitation and the thermoviscous phenomena in the hole and the pipe. If a wave positioned 1 mm from the wall of the pipe generates an external wall pressure in the range of 152 dB at the surface of the hole, the pressure in the pipe is uniform and in the range of 148 dB.

[0062] Therefore, the 4 dB attenuation caused by the hole crossing and the related thermoviscous effects is relatively low and quite acceptable considering the acoustic emission level of the arc and the dynamics of the microphone 7.

[0063] The unattenuated propagation of the acoustic wave OA in the inner space 12 of the probe 10 and the good detection of the acoustic wave OA also rely on the good acoustic isolation of the inner space 12 from external noise.

[0064] exist Figure 3 In the example of , acoustic isolation (in the vulnerable areas 15, outside these areas 15) is ensured by the wall 4. Figures 4 to 6 In the example of , the acoustic isolation is ensured by the membrane 3 in the vulnerable areas 15 and by the wall 4 outside these areas 15. In this regard, it should be noted that the cylindrical shape of the wall 4 and the membrane 3 greatly contributes to the acoustic isolation provided. In fact, the curvature of the wall 4 and the membrane 3 leads to the appearance of a frequency called the ring frequency, below which the sound insulation index increases further with lower frequencies of the sound waves. This ring frequency is the frequency at which the longitudinal wavelength corresponds to the circumference of the cylinder. Thus, for a pipe with an outer diameter of 4 mm, with a 1 mm thick elastomer wall and a ring frequency in the range of 76000 Hz, the theoretical sound insulation index is greater than 90 dB for frequencies less than 200 Hz. In contrast, for a plate made of 1 mm thick elastomer (without radius of curvature), the theoretical sound insulation index is only in the range of 5 dB to 6 dB. A method for detecting and locating an electric arc will now be described. Reference Fig.10In this figure, the detection device includes a probe 10, which includes a vulnerable area 15 distributed along the probe. The probe 10 can be similar to Figure 3 or Figure 4 The device also includes a series of microphones arranged so that at least two microphones 71, 72 arranged on either side of the vulnerable area 15 affected by the arc AR can detect the acoustic wave OA generated by the arc and propagating in the probe 10. For example, the spacing between two adjacent microphones 71, 72 can be metric. For example, the spacing can be comprised between 2 meters and 20 meters, more specifically, the spacing can be comprised between 5 meters and 20 meters.

[0065] The ends or terminals of the probe 10 are open to the outside or are equipped with plugs for absorbing sound waves to avoid the phenomenon of sound waves being reflected at these ends (i.e., echo phenomenon). The sound wave OA propagates at a speed c on either side of the vulnerable area 15 and is sensed by the two microphones 71, 72 at times t1 and t2, respectively. The distance separating the vulnerable area 15 from the first microphone 71 is recorded as d1, and the distance separating the vulnerable area 15 from the second microphone 72 is recorded as d2. The sound wave OA is sensed by the microphones 71, 72 with a time offset (t2-t1), which represents the difference in the distance traveled. In this case:

[0066] [Mathematics 1]

[0067] d2-d1=c(t2-t1)

[0068] The distance L=d1+d2 between the microphones is predetermined, and the position of the arc AR relative to the microphone 71 can then be easily derived according to the following equation:

[0069] [Mathematics 2]

[0070]

[0071] The calculation is performed by a calculation unit (not shown) of the device for receiving the measurement signals from the microphones 71 , 72 .

[0072] This method of locating the electric arc AR has the advantages of being reliable and relatively simple. However, other methods can also be considered for locating the electric arc based on the measurement signal of the acoustic sensor.

[0073] For example, where the terminals of the probe 10 reflect acoustic waves, the time signal at the output of the acoustic sensor represents the incident wave and the reverse wave propagated by the nearest terminal. The time offset between wave detections and the distance between the acoustic sensor and the terminal can determine the location of the arc.

[0074] According to another example, a frequency analysis may be performed using an acoustic propagation model of plane waves with visco-thermal attenuation and calculation of the autospectrum (SPLdB) of the acoustic sensor to infer the location of the arc.

[0075] The embodiments described in the present disclosure are for illustrative and non-limiting purposes only, and those skilled in the art can easily modify these embodiments or consider other embodiments based on the present disclosure while still within the scope of the present invention.

[0076] Specifically, if some features of the above-described embodiments are sufficient to provide one of the advantages of the present invention alone, a person skilled in the art will be able to easily conceive of variants that include only these features. In addition, the different features of these embodiments can be used alone or in combination with each other. When combined, these features can be described as described above or differently, and the present invention is not limited to the specific combinations described herein. Specifically, unless otherwise stated, the features described in conjunction with one embodiment can be similarly applied to another embodiment.

Claims

1. A device for acoustic detection of electric arcs, said device comprising a tubular probe (10) adapted to be arranged next to an electrical device on which an electric arc (AR) may form, in, An interior space (12) defined by the walls (4) of the probe extends along the length of the probe (10), the interior space (12) being filled with a fluid and being acoustically isolated from external noise by the walls (4), The probe (10) comprises at least one vulnerable area (15), the at least one vulnerable area (15) being located at the periphery of the inner space (12) of the probe (10) and on the wall (4) of the probe (10), the at least one vulnerable area (15) being adapted to degrade under the action of the electric arc (AR) so as to expose a passage (16) for the acoustic wave (OA) generated by the electric arc to pass to the inner space, The device further comprises at least one acoustic sensor (7, 71, 72) adapted to detect sound waves travelling through the channel (16) and propagating in the inner space (12) of the probe.

2. The device according to claim 1, wherein: The at least one vulnerable zone (15) is a fusible zone adapted to melt under the effect of heat generated by the electric arc (AR).

3. The device according to claim 2, wherein: The fusible area is formed by a fusible film (3) covering an opening (5) through the wall.

4. The device according to claim 3, wherein: The fusible film (3) covers the entire wall (4) from the outside or the inside.

5. The device according to claim 3 or 4, wherein: The fusible film (3) has the ability to shrink under the action of heat.

6. The device according to claim 1 or 2, wherein: The at least one vulnerable area (15) is formed by a region of reduced thickness of the wall (4).

7. The device according to any one of claims 1 to 6, comprising a plurality of vulnerable areas (15) distributed along the probe (10).

8. The device according to any one of claims 1 to 7, wherein: The fluid is air.

9. The device according to any one of claims 1 to 8, wherein: A tube (6) extends from the interior space (12) of the probe through the wall (4) to the acoustic sensor (7, 71, 72).

10. The device according to any one of claims 1 to 9, wherein: The acoustic sensor (7, 71, 72) is suitable for detecting sound waves (OA) with a frequency less than 1000 Hz, and in particular, the acoustic sensor (7, 71, 72) is suitable for detecting sound waves (OA) with a frequency less than 500 Hz.

11. The device according to any one of claims 1 to 10, wherein: The cross-section of the inner space (12) of the probe is large enough so that the acoustic attenuation along the probe (10) is less than 2 dB / m for sound waves with a frequency comprised between 100 Hz and 500 Hz.

12. The device according to any one of claims 1 to 11, further comprising a computing unit, configured to determine a propagation time of the sound wave from the degraded vulnerable area (15) to the acoustic sensor based on a measurement signal from at least one of the acoustic sensors (7, 71, 72), and to infer the position of the arc (AR) based on the propagation time.

13. An assembly comprising a device according to any one of claims 1 to 12 and a wiring harness (20) comprising a plurality of cables (1), wherein: The probe (10) is integrated into the wiring harness and arranged along the cable (1).

14. The assembly according to claim 13, wherein The cable (1) is distributed circumferentially around the probe (10).

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